1. Field of the Invention
The present invention generally relates to a multi-level point-to-point transmission system and a transmitter circuit and a receiver circuit thereof, in particular, to a multi-level point-to-point transmission system and a transmitter circuit and a receiver circuit thereof applied in a large-sized display panel.
2. Description of Related Art
The techniques for fabricating display panels have gradually reached their maturity in recently years. However, the sizes and resolutions of display panels have been increased constantly in order to meet customers' requirement. However, the operation frequency inside a display panel will be increased along with the increases in the resolution and size of the display panel. A conventional transmission system in a display panel has to be disposed with a plurality of pairs of transmission lines such that it is almost impossible to make all the transmission lines to have similar electrical characteristics in a high-frequency ambient. Thus, no effective correction mechanism for correcting foregoing problem can be provided at a receiving terminal and accordingly the bit error rate of the transmission system cannot be reduced. In particular, additional cost is incurred for resolving foregoing problem in the transmission system so that product competitiveness cannot be improved.
FIG. 1A is a diagram of a conventional transmission system in a liquid crystal display (LCD) panel. The transmission system includes a timing controller TCON and a plurality of drive ICs SD1, SD2 . . . , and SDN. The timing controller TCON transmits a video data to the drive ICs SD1˜SDN in the LCD panel through a pair of clock transmission lines and a plurality of pairs of transmission lines. Each pair of transmission lines is coupled to the input terminals of all the drive ICs SD1˜SDN. FIG. 1B is a detailed circuit diagram of the transmission system in FIG. 1A. The timing controller TCON serves as a transmitter circuit, and the drive ICs SD1˜SDN serve as receiver circuits. The timing controller TCON and the drive ICs SD1˜SDN form the transmission system. The single to differential converters TX1, TX2, TX3, . . . , TXN, and TXCK output the input data DI_1, DI_2, DI_3, . . . , and DI_N and an input clock signal CKI to the comparators RX1, RX2, RX3, . . . , RXN, and RXCK at the receiving terminals of the drive ICs SD1˜SDN. The comparators RX1, RX2, RX3, . . . , RXN, and RXCK at the receiving terminals of the drive ICs SD1˜SDN compare the signed signals to obtain corresponding digital values 1 or 0. However, this transmission system has very complicated circuit layout, heavy transmission load, and high noise influence therefore is not suitable for a high-frequency and large-sized LCD panel.
Generally, a conventional transmission system in a display panel includes a plurality of pairs of transmission lines, wherein a data received by a receiving terminal can be easily decoded by using a simple comparator.
Along with the increase in the sizes of display panels, a multi-level point-to-point transmission mechanism has to be adopted in the transmission system of a display panel in order to reduce the transmission frequency and accordingly the transmission line effect. However, as to a receiving terminal in the multi-level point-to-point transmission system, a set of precise level comparators instead of a simple comparator is required for decoding a received data. Moreover, in a medium or large-sized display panel, all the drive ICs are controlled by the same control IC, thus, a reference voltage level at the receiving terminal of each drive IC has to be consistent with a reference voltage level at the transmitting terminal thereof in order to prevent decoding error.
As described above, by adopting a multi-level point-to-point transmission system in a large-sized display panel, the design complexity of the large-sized display panel can be greatly reduced. However, a receiving terminal in a multi-level point-to-point transmission system has to generate a reference voltage level as same as that at a transmitting terminal in order to decode a transmission data correctly, which is very difficult to be achieved due to the difference between processes. Thus, a built-in fine tune mechanism is usually adopted for offsetting the difference between processes. In addition, how to provide a same fine tune mechanism to each of the drive ICs in a display panel is to be resolved by today's display manufacturers.